Co-reporter:Changzhi Zhao;Licheng Liu;Junying Ge;Yanyan He
Microchimica Acta 2017 Volume 184( Issue 7) pp:2333-2339
Publication Date(Web):26 April 2017
DOI:10.1007/s00604-017-2230-3
A photoelectrochemical sensor for FAD and FMN was fabricated by incorporating the reduced flavin cofactor as an electron donor into a photoelectrochemical reaction in a ZnO nanorod photoelectrode (ZnO-NR-PhE). The assay is based on the pre-reduction of the flavin coenzyme on a second working electrode. The ZnO-NR-PhE was electrochemically preparated, and synthesis was optimized. The mechanism of the reaction of flavin coenzyme on the ZnO-NR-PhE was studied. Under optimized conditions (a pH value of 6.5; a pre-reduction potential of −0.40 V; illumination at 365 nm; a light energy of 1.6 mW∙cm−2), the photocurrent at a bias voltage of 0.1 V is proportional to the logarithm of the coenzyme concentration in the range from 10 nmol⋅L−1 to 1.0 μmol⋅L−1. The detection sensitivity is 193.5 nA/logC (μmol⋅L−1) for FMN, and 195.6 nA/logC (μmol⋅L−1) for FAD. The respective detection limits are 8.0 and 5.0 nmol⋅L−1 (at an S/N ratio of 3), respectively. Compared to other methods, the one presented here has a wide analytical range, high sensitivity, and convenient operation. Common biochemical substances do not interfere.
Co-reporter:Wei Li;Junying Ge ;Changzhi Zhao
Luminescence 2015 Volume 30( Issue 6) pp:853-858
Publication Date(Web):
DOI:10.1002/bio.2832
Abstract
A highly sensitive and selective method for the determination of cholesterol is required to evaluate trace amounts of cholesterol in test samples. In this work, selected gold nanoparticles (AuNPs) and 5-amino-2-mercapto-1,3,4-thiadiazole (AMT) were used and a thin film of three-dimensional gold–AMT core–shell nanoparticles (p-AMT–AuNPs) was prepared using an electrochemical method. Cholesterol oxidase was then bonded to the film surface to give a functional electrode. Based on catalysis by the electrode functionalized for cholesterol and a luminol–H2O2 electrochemiluminescence (ECL) system, a highly sensitive and selective ECL method was developed for the determination of cholesterol. Under optimized conditions, ECL intensity showed a good linear relationship with cholesterol over the concentration range 0.05–11.0 µg/ml, with a correlation coefficient of 0.999 and a limit of detection of 0.02 µg/ml. The proposed method was used to determine cholesterol in dairy products with a relative standard deviation of < 1.8% and recovery rates of 98.1–104%. Copyright © 2015 John Wiley & Sons, Ltd.
Co-reporter:Chang-Zhi Zhao, Jun-Yu Liang, Xiao-Lei Gu, Hui Liu
Chinese Chemical Letters 2014 Volume 25(Issue 2) pp:370-374
Publication Date(Web):February 2014
DOI:10.1016/j.cclet.2013.11.013
The present study reports a sensitive electro-analytical method for the simultaneous determination of dihydroxybenzene isomers by using a thiadiazole film electrode, which was readily prepared by electropolymerization of 2,5-dimercapto-1,3,4-thiadiazole on a glassy carbon electrode with cyclic voltammetry. The functionalized electrode has a distinguishable and sensitive response to dihydroxybenzene isomers. Under the optimized conditions, the linear stripping peak currents showed good linear relationships with hydroquinone, catechol and resorcinol at concentration ranges 0.50–120, 0.50–110 and 1.00–110 μmol/L, and the detection limits are 0.1, 0.1 and 0.3 μmol/L, respectively. The proposed method is applicable to the simultaneous determination of dihydroxybenzene isomers in real samples with the relative standard deviations of less than 5.7% and the recovery rates of 95.6%–106%. The constructed electrode is characterized by simple preparation, good selectivity, and high sensitivity advantages.Dihydroxybenzene isomers were simultaneously determined utilizing a thiadiazole film electrode.
Co-reporter:Zhao-Xia ZHANG, Chang-Zhi ZHAO
Chinese Journal of Analytical Chemistry 2013 Volume 41(Issue 3) pp:436-444
Publication Date(Web):March 2013
DOI:10.1016/S1872-2040(13)60637-4
The photoelectrochemical process is an electrochemical process based on the light signal. During electrochemical process, photocurrent is generated by electron transfer between some of the substances and the excited states of optoelectronic materials. The photoelectrochemical analysis method has a great application potential for analytical chemistry due to the good selectivity, the high sensitivity, the simple equipment and the easy miniaturization. In this paper, the studies on progress of photoelectrochemical analysis method and its derived sensors are reviewed of 84 references published in recently years.
Co-reporter:Changzhi Zhao;Zhaoxia Zhang;Ying Zhao ;Jia Yu
Chinese Journal of Chemistry 2012 Volume 30( Issue 8) pp:1851-1856
Publication Date(Web):
DOI:10.1002/cjoc.201200318
Abstract
A new photoelectrochemical method for the determination of glucose based on the photoelectrochemical effect of poly(thionine) photoelectrode to hydrogen peroxide (H2O2) was reported. The H2O2-sensitive photoelectrode was fabricated by electropolymerizing thionine on the surface of ITO electrode. And then glucose oxidase was immobilized on the photoelectrode via the aid of chitosan enwrapping, forming an enzyme-modified photoelectrode. The photoelectrode was employed as an electron acceptor; H2O2 from the catalytic reaction of enzyme was employed as an electron donor, developing an analytical method of glucose without hydrogen peroxidase. In the paper, the photoelectrochemical effects of photoelectrode to H2O2 and glucose were studied. The effects of the bias voltage and the electrolyte pH on the photocurrent were investigated. The linear response of glucose concentrations ranged from 0.05 to 2.00 mmol/L was obtained with a detection limit of 22.0 µmol/L and sensitivity of 73.2 nA/(mmol·L−1). The applied feasibility of method was acknowledged through monitoring the glucose in practical samples.
Co-reporter:Changzhi Zhao, Hui Liu and Li Wang
Analytical Methods 2012 vol. 4(Issue 11) pp:3586-3592
Publication Date(Web):28 Aug 2012
DOI:10.1039/C2AY25525A
The present study reports a sensitive electro-analytical method for the simultaneous determination of trace lead (Pb(II)) and cadmium (Cd(II)) using a non-mercury electrode modified with the electropolymerized thiadiazole film. The electropolymerization of 2,5-dimercapto-1,3,4-thiadiazole on a glassy carbon electrode is carried out, and differential pulse anodic stripping voltammetry for the simultaneous determination of trace Pb(II) and Cd(II) is developed by using this modified electrode as the working electrode. In 0.1 mol L−1 acetate buffer solution at pH 5.5, the stripping peak currents after enrichment at −1.20 V for 300 s showed good linear relationships with Pb(II) and Cd(II) at concentration ranges of 1.00–200 and 0.50–200 μg L−1, and the detection limits are 0.30 and 0.05 μg L−1, respectively. The proposed method is applicable to the simultaneous determination of trace Pb(II) and Cd(II) in real water samples with the relative standard deviations of less than 5.7% and the recovery rates of 97.6–106%. The good response of the prepared electrode to Pb(II) and Cd(II) is attributed to the binding of thiol groups and the electrostatic interaction between the modified electrode with metal ions. The findings indicate that the proposed method is helpful in monitoring toxic elements in environmental waters.
Co-reporter:Chang-Zhi ZHAO, Jia YU, Gai-Shuang ZHAO, Kui JIAO
Chinese Journal of Analytical Chemistry 2011 Volume 39(Issue 6) pp:886-889
Publication Date(Web):June 2011
DOI:10.1016/S1872-2040(10)60448-3
A novel choline biosensor based on the chitosan-immobilized choline oxidase on a poly(thionine)-modified ITO electrode (PThE) is described in this article. In this study, the photosensitive PThE was employed as an electron acceptor, and H2O2 produced by the catalytic reaction was employed as an electron donor, developing a photoelectrochemical choline biosensor. The photoelectrochemical responses of biosensor to H2O2 and choline were studied. The effects of bias voltage, light intensity and pH of electrolyte on photocurrent were investigated. The linear response of choline concentrations ranging from 0.05 to 2.00 mM was obtained with a detection limit of 30.0 μM and a sensitivity of 65.7 μA M−1. The applied feasibility of biosensor was acknowledged by monitoring the phosphatidylcholine in lecithin samples. The prepared biosensor is economical, rapid, simple and convenient to detect the choline without hydrogen peroxidase.
Co-reporter:Changzhi Zhao, Li Wan, Li Jiang, Qin Wang, Kui Jiao
Analytical Biochemistry 2008 Volume 383(Issue 1) pp:25-30
Publication Date(Web):1 December 2008
DOI:10.1016/j.ab.2008.08.022
A cholesterol biosensor based on direct electron transfer of a hemoglobin-encapsulated chitosan-modified glassy carbon electrode has been developed for highly sensitive and selective analysis of serum samples. Modified by films containing hemoglobin and cholesterol oxidase, the electrode was prepared by encapsulation of enzyme in chitosan matrix. The hydrogen peroxide produced by the catalytic oxidation of cholesterol by cholesterol oxidase was reduced electrocatalytically by immobilized hemoglobin and used to obtain a sensitive amperometric response to cholesterol. The linear response of cholesterol concentrations ranged from 1.00 × 10−5 to 6.00 × 10−4 mol/L, with a correlation coefficient of 0.9969 and estimated detection limit of cholesterol of 9.5 μmol/L at a signal/noise ratio of 3. The cholesterol biosensor can efficiently exclude interference by the commonly coexisting ascorbic acid, uric acid, dopamine, and epinephrine. The sensitivity to the change in the concentration of cholesterol as the slope of the calibration curve was 0.596 A/M. The relative standard deviation was under 4.0% (n = 5) for the determination of real samples. The biosensor is satisfactory in the determination of human serum samples.
Co-reporter:Changzhi Zhao, Changli Shao, Minghua Li, Kui Jiao
Talanta 2007 Volume 71(Issue 4) pp:1769-1773
Publication Date(Web):15 March 2007
DOI:10.1016/j.talanta.2006.08.013
This paper reports a flow-injection analysis (FIA) of glucose not using enzyme based on the electrocatalytic oxidation of glucose at a nickel electrode. The electrocatalytic mechanism and quantificational method of glucose have been investigated. The current intensity of the electrocatalytic oxidation to glucose at the potential of 550 mV is proportional to the concentration of glucose over the range of 0.10–2.50 mmol l−1, with a 0.04 mmol l−1 detection limit (S/N = 3) and a correlation coefficient of 0.9991. The relative standard deviation (R.S.D.) is less than 4.3% (n = 5) for the determination of practical serum samples. The biologic compounds probably existed in the sample, such as ascorbic acid, uric acid, dopamine and epinephrine, do not disturb the determination of glucose. The result is satisfactory for the determination of glucose in human serum sample as comparison to that from the routine hexokinase method.
Co-reporter:Changzhi Zhao, Hui Liu and Li Wang
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 11) pp:NaN3592-3592
Publication Date(Web):2012/08/28
DOI:10.1039/C2AY25525A
The present study reports a sensitive electro-analytical method for the simultaneous determination of trace lead (Pb(II)) and cadmium (Cd(II)) using a non-mercury electrode modified with the electropolymerized thiadiazole film. The electropolymerization of 2,5-dimercapto-1,3,4-thiadiazole on a glassy carbon electrode is carried out, and differential pulse anodic stripping voltammetry for the simultaneous determination of trace Pb(II) and Cd(II) is developed by using this modified electrode as the working electrode. In 0.1 mol L−1 acetate buffer solution at pH 5.5, the stripping peak currents after enrichment at −1.20 V for 300 s showed good linear relationships with Pb(II) and Cd(II) at concentration ranges of 1.00–200 and 0.50–200 μg L−1, and the detection limits are 0.30 and 0.05 μg L−1, respectively. The proposed method is applicable to the simultaneous determination of trace Pb(II) and Cd(II) in real water samples with the relative standard deviations of less than 5.7% and the recovery rates of 97.6–106%. The good response of the prepared electrode to Pb(II) and Cd(II) is attributed to the binding of thiol groups and the electrostatic interaction between the modified electrode with metal ions. The findings indicate that the proposed method is helpful in monitoring toxic elements in environmental waters.
